Method for corrosion prevention

ABSTRACT

The composition described herein for the prevention of corrosion comprises: sacrificial metal particles more noble than a metal substrate to which the composition contacts; carbonaceous material that can form electrical contact between the sacrificial metal particles; and means for providing an anticorrosion coating material for the metal substrate. The composition can form a coating on a metal substrate surface. A method for applying the composition for the prevention of corrosion is also described herein.

This application is a continuation of U.S. Ser. No. 15/937,980, filedMar. 18, 2018, now U.S. Pat. No. 10,074,454, which is a continuation ofU.S. Ser. No. 13/600,939, filed Aug. 31, 2012, now U.S. Pat. No.9,953,759, entitled COMPOSITION FOR CORROSION PREVENTION, which claimspriority to a provisional application having U.S. Ser. No. 61/529,471,entitled COMPOSITION FOR CORROSION PREVENTION, filed Aug. 31, 2011.

BACKGROUND A. Field of Art

Described herein are compositions and methods that can preventcorrosion. More specifically, the compositions and methods describedprovide corrosion prevention of metal submerged in salt water and metalused in crude oil pipes.

B. Description of the Related Art

Corrosion is the inevitable gradual destruction of material, usuallymetal, by chemical reaction with its environment. These metals aremainly iron and steel, although many other metals may corrode as well.This corrosion is typically due to oxidation, which can be acceleratedin the presence of moisture, to form a metal oxide. Many structuralalloys corrode merely from exposure to moisture in the air, but theprocess can be strongly affected by exposure to certain substances. Forexample, when iron is exposed to moist air, it reacts with oxygen toform rust, Fe₂O₃nH₂O. Coating the surface of the iron-containing articlemay help to shield the article from the elements needed for the naturalrusting reaction to begin.

Corrosion can be concentrated locally, or it can extend across a widearea more or less uniformly corroding the surface. Because corrosion isa diffusion controlled process, it occurs on exposed surfaces. Theproblem with iron as well as many other metals is that the oxide formedby oxidation does not firmly adhere to the surface of the metal andflakes off easily causing “pitting” and/or “cracking.” Extensive pittingand/or cracking may eventually cause structural weakness, a decrease inluster, a decrease of electrical conductivity, and a disintegration ofthe metal. Because of this structural disintegration and weakening, theeffects of corrosion may cost millions of dollars each year, with muchof this loss from the corrosion of iron and steel.

II. SUMMARY

A new and improved composition for providing corrosion protection isdescribed herein. One composition comprises: sacrificial metal particlesmore noble than a metal substrate to which the composition contacts; andcarbonaceous material that can form electrical contact between thesacrificial metal particles; and a means for providing an anticorrosioncoating material for the metal substrate.

Another aspect of the composition is to provide sacrificial metalparticles that resist oxidation of iron(II) ion into iron(III) ion.

Still another aspect of the composition is to provide sacrificial metalparticles that comprise at least one metal of nickel, cobalt, and/ormolybdenum.

Still yet another aspect of the composition is to provide sacrificialmetal particles that are microparticles or nanoparticles.

One aspect of the composition is to provide sacrificial metal particlesthat comprise about 0.00001% by weight to about 95% by weight of thecomposition.

Yet another aspect of the composition is to provide sacrificial metalparticles that are regenerated.

Another aspect of the composition is to provide metal substrate that isat least one metal of iron, copper, nickel, titanium, silver, aluminum,steel, and/or stainless steel.

Still another aspect of the composition is to provide carbonaceousmaterial that comprises graphitic carbon.

Yet another aspect of the composition is to provide graphitic carbonthat comprises at least one graphitic carbon of microhorns,single-walled nanotubes, double-walled nanotubes, multi-wallednanotubes, graphite, and/or graphene.

Still yet another aspect of the composition is to provide carbonaceousmaterial that is functionalized.

One aspect of the composition is to provide carbonaceous material thatcomprises about 0.1% by weight to about 20% by weight of thecomposition.

Another aspect of the composition is to provide carbonaceous materialthat comprises about 0.1% by weight to about 4% by weight of thecomposition.

Still another aspect of the composition is to provide a flowablematerial that is an anticorrosion coating material for the metalsubstrate.

Another aspect of the composition is to provide a flowable materialcomprising at least one polymer of polyacrylate, polyacrylonitrile,polybitumeate, polyethylene, polypropylene, polybutadiene, polyurea,polyamide, polyimide, polyurethane, polyvinylchloride, aspartates,fluoropolymers, silicone, siloxanes, rubber, and/or epoxy.

Yet another aspect of the composition is to provide a flowable materialthat is polymerized on the surface of a metal substrate.

Still yet another aspect of the composition is to provide a flowablematerial that is dissolved in at least one solvent. Another aspect ofthe composition is that the solvent is at least one solvent ofdimethylformamide, dimethylsulfoxide, ethylene carbonate, acetonitrile,2-propanol, acetone, butanone, ethyl acetate, and/or toluene.

Still another aspect of the composition is to provide a flowablematerial that is capable of forming a solid film or coating on thesurface of the metal substrate.

Another aspect of the composition is to provide a powder coating that isan anticorrosion coating material for the metal substrate.

Still yet another aspect of the composition is to further provide thecomposition with cellulose.

One aspect of the composition is to provide the composition furthercomprising cellulose where the cellulose is functionalized celluloseand/or amorphous fragmented cellulose.

Another aspect of the composition is to further provide the compositionwith an antioxidant.

Another aspect of the composition is to provide antioxidants thatcomprise at least one antioxidant of hydrochinon, tannic acid, lignin,lignin fragments, polyunsaturated fats, esters of polyunsaturated fats,and/or pine oil.

Still another aspect of the composition is to further provide thecomposition with aluminum i-propoxide.

Yet another aspect of the composition is to further provide thecomposition with trimethyl borate.

Still yet another aspect of the composition is to further provide thecomposition with at least one ligand.

One aspect of the composition is to provide the ligand in which theligand bonding comprising of at least one group of carboxylic, amino,hydroxyl amino, and/or cyano groups.

Yet another aspect of the composition is to further provide thecomposition with lead oxide.

Still another aspect of the composition is to further provide thecomposition with at least one compound of silica, alumina, titaniumoxide, copper oxide, and/or tin oxide.

Still yet another aspect of the composition is to further provide thecomposition with at least one compound of silica, alumina, titaniumoxide, copper oxide, and/or tin oxide is a microparticle or ananoparticle.

Another aspect of the composition is to further provide the compositionwith sacrificial metal particles less noble than the metal substrate towhich the composition contacts.

A method of protecting a metal substrate is also described hereincomprising the step of applying and/or contacting the composition to ametal substrate wherein the composition comprises: sacrificial metalparticles more noble than a metal substrate to which the compositioncontacts and carbonaceous material that can form electrical contactbetween the sacrificial metal particles, wherein the compositionprovides an anticorrosion coating material for metal.

Still another aspect of the composition is that the composition providesan anticorrosion coating material for metal comprising: a flowablematerial comprising epoxy functionalities; sacrificial metal particlesmore noble than a metal substrate to which the composition contactscomprising at least one metal of nickel and/or cobalt; carbonaceousmaterial comprising multi-walled graphitic carbon that can formelectrical contact between the sacrificial metal particles; anantioxidant comprising at least one antioxidant of hydrochinon, tannicacid, lignin, lignin fragments, polyunsaturated fats, esters ofpolyunsaturated fats, and/or pine oil; and means for providing ananticorrosion coating material for metal.

Still other benefits and advantages will become apparent to thoseskilled in the art to which it pertains upon a reading and understandingof the following detailed specification.

III. DETAILED DESCRIPTION

Referring now to the description, wherein the descriptions may be forpurposes of illustrating embodiments only and not for purposes oflimiting the same, the present application may aid in illustrating thecomposition and method described herein.

Corrosion is the gradual destruction of material, usually metals, bychemical reaction with its environment. Described herein is acomposition and a method for the prevention of corrosion, including thecorrosion of iron under salt water and in crude oil pipes. By preventingor at least reducing corrosion, there can be an elimination or reductionof damage to the metal substrate.

In assessing the potential for corrosion, the type of metal may beconsidered. Table A (below) shows a galvanic corrosion table, whichprovides a comparison of different metals for galvanic corrosionaccording to their relative activity in seawater. Although Table A onlyprovides a sampling of metals, it should not be considered limiting asto the type of potential metals that could be used. The anodic metals atthe top of Table A are least noble, whereas the metals at the bottom ofTable A are cathodic, or most noble. The further apart the metals, thehigher the risk of galvanic corrosion for the metal. For the metalslisted in Table A, the voltage difference between two metals can drivethe current flow to accelerate corrosion of the anodic metal. The twomajor factors affecting the severity of galvanic corrosion are: (1) thevoltage difference between the two metals on the Galvanic Series and (2)the size of the exposed area of cathodic metal relative to that of theanodic metal. Corrosion of the anodic metal is both more rapid and moredamaging as the voltage difference increases and as the cathode areaincreases relative to the anode area.

TABLE A

A composition described herein may provide a means for providing ananticorrosion coating material for metal. The composition may comprisecarbonaceous material that can form electrical contact betweensacrificial metal particles, wherein the sacrificial metal particles canbe more noble than a metal substrate to which the composition contacts.Also described is a method of protecting a metal substrate using thecomposition described herein, which comprises sacrificial metalparticles more noble than a metal substrate to which the composition maybe applied, and carbonaceous material that can form electrical contactbetween the sacrificial metal particles.

The list in Table A represents the potential to promote a corrosivereaction; however, the actual corrosion in each application can bedifficult to predict. Typically, corrosion may be reduced or eliminatedthrough the use of certain coatings with galvanic metals that offersacrificial anodic protection. Nevertheless, the oxidation potentialsprovided, as seen in Table A, are measured in water solution for baremetals. However, the oxidation potentials may change when measured inpolymeric matrices, especially if the polymer or added ligandcoordinates with sacrificial and protected metal differently. Withinthese polymeric systems used for corrosion protection, includingcathodic protective coatings that may contain polymeric matrices, theactual oxidation potentials may be different than the potentialsprovided in Table A. In order to provide the composition describedherein, the oxidation potential can be measured within the polymericmatrices in order to determine whether it is more noble than the metalto be protected.

For the composition described herein, the sacrificial metal particlesmore noble than a metal substrate to be protected may be dispersedwithin the composition. These sacrificial metal particles can resistoxidation of iron(II) ion into iron(III) ion, which can provideprotection from corrosion when they are more noble than a metalsubstrate to which the composition contacts. For example, thesesacrificial metal particles may comprise at least one metal of nickel,cobalt, and/or molybdenum. Although the metal substrate may form aprotective layer, the sacrificial metal particles more noble than ametal substrate to be protected may provide corrosion protection. Forexample, an iron substrate can form a hard protective layer ofiron(II)oxide. The gradual slow thickening of iron(II)oxide layer maynot be detrimental because an iron surface can be coated with theiron(II)oxide layer even before the composition described herein. Thesacrificial metal particles more noble than a metal substrate to beprotected may then prevent or at least reduce the further oxidation ofiron(II)oxide into iron(III)oxide, since corrosion may only be formedwhen the iron(II)oxide is oxidized into iron(III)oxide. While some ofthese sacrificial metal particles can be oxidized, the particles may beon electric contact with the iron(II)oxide through the use of carbonnanotubes or other graphitic material where the underlying iron can be asemiconductor. The oxidation of the sacrificial metal particles morenoble than a metal substrate to be protected can lead to a prevention orreduction of the sacrificial metal particles and a thickening ofiron(II)oxide layer. Most notably, the formation of iron(III)oxide canbe prevented or at least reduced.

In the composition, the sacrificial metal particles more noble than ametal substrate to be protected may comprise about 0.00001% by weight toabout 95% by weight. The sacrificial metal particles more noble than ametal substrate can also be microparticles, which may be about 0.1 μm toabout 300 μm in size. The sacrificial metal particles more noble than ametal substrate can also be nanoparticles, which may be about 1 nm andabout 2500 nm in size. Where microparticles or nanoparticles are used,the composition of the sacrificial metal particles more noble than ametal substrate may be 0.00001% by weight. These sacrificial metalmicroparticles or nanoparticles may be easier to handle because theywill not be so easily oxidized. Further, the sacrificial metal particlesmore noble than a metal substrate may be regenerated. Regeneration mayprovide a means to continuous corrosion prevention. The regeneration maybe completed by a periodic external potential. Because of theregeneration option, the composition may only require a small amount ofthe sacrificial metal particles more noble than a metal substrate.

The metal substrate described herein may be at least one metal of iron,copper, nickel, titanium, silver, aluminum, steel and/or stainlesssteel, but is not limited to those listed herein. The metal substratemay comprise a variety of shapes and sizes. The metal substrate may alsobe protected with other coatings for the prevention of corrosion. Themetal substrate may be cleaned prior to the application of thecomposition described herein.

The carbonaceous material of the composition may comprise graphiticcarbon. The graphitic carbon may comprise at least one graphitic carbonof microhorns, single-walled nanotubes, double-walled nanotubes,multi-walled nanotubes (also can be referred to as MWNT), graphite,and/or graphene. For example, MWNT may be used. For the composition, arelatively small amount of a carbonaceous material can allow foradequate conductivity. The carbonaceous material may comprise about0.01% by weight to about 20% by weight of the composition. Further, thecarbonaceous material may comprise about 0.1% by weight to about 4% byweight of the composition. In order to obtain increased conductivity, ahigher loading level of graphitic carbon may be needed. In addition toelectrical conduction, graphitic carbon may add strength of the coating.Liquid, such as salt water, can seep though cracks under the coating andcorrosion will spread around cracks, which may cause the coating togradually peel off. The use of graphitic carbon can help to diminishand/or prevent cracks, therefore reducing corrosion. Additionally, thecarbonaceous material can also be functionalized.

The composition described herein may also contain flowable material. Theflowable material may be liquid. The flowable material may be a plasticor a resin. The flowable material may comprise at least one polymer ofpolyacrylate, polyacrylonitrile, polybitumeate, polyethylene,polypropylene, polybutadiene, polyurea, polyamide, polyimide,aspartates, fluoropolymers, polyurethane, polyvinylchloride, silicone,siloxanes, rubber, and/or epoxy. During the formation of oxide frommetal, the volume of the metal particle can increase; therefore, someelastic material like a polymer may be added near these particles.

The flowable material can be capable of forming a solid film or coatingon the metal substrate surface. In order to prevent or reduce corrosion,flowable material can be polymerized onto the metal surface of thesubstrate to be protected. The flowable material may also be melted.Furthermore, the flowable material may be dissolved in at least onesolvent. The solvent(s) may include at least one solvent ofdimethylformamide, dimethylsulfoxide, ethylene carbonate, acetonitrile,2-propanol, acetone, butanone, ethyl acetate, and/or toluene. Thesolvents listed above are not limiting, and in some cases, a widevariety of solvents may be used. However, the health and/or safetyaspects of a solvent may dictate which solvents may be used. Twocomponent or multiple component resin systems can also be used in thecomposition described herein. With two component polymers, no solventmay be needed when least one component is liquid. Also in such caseswhen polymerization is done in situ, solvent can be the monomer itself.One example of this may be with some acrylates, where the solvent canbe, for example, methylmethacrylate.

Many plastics or resins may be used as a flowable material in thecoating, as described above. When plastics or resins of the compositionare in liquid state prior to curing, graphitic carbon like MWNT canprovide an electrically conducting path. However, when these plastic orresin materials solidify, the conductivity may disappear because thematerial can surround the graphitic carbon, separating the graphiticcarbon from each other. This can be seen with epoxies, for instance. Theseparation can be prevented by using cellulose, functionalizedcellulose, and/or amorphous fragmented cellulose as a carrier within thecomposition. These materials can wrap around the MWNT and prevent themfrom separation during curing.

Besides using a flowable material, the composition described can becapable of forming a solid film or coating without the use of a flowablematerial. For example, the non-flowable composition may be a powdercoating. Providing various forms of the composition described herein canoffer other potential applications and/or application methods for thecomposition.

Additionally, other additives may help to maintain electricalconductivity. Some examples can be aluminum isopropoxide and/ortrimethyl borate. These additives that may help to maintain electricalconductivity can neutralize the surface charge of the MWNT so thatCoulombic repulsion does not push them apart. Another additive that maybe used is ligands. Ligands may also change the oxidation potentials tothe extent that the galvanic order may change. If ligand binding withion is strong, then oxidation may be facilitated. Carboxylic, amino,hydroxyl amino, and/or cyano groups can be examples of strong ligands.Thus, polyacrylic acid, polyalkyl amine, amino hardened epoxy, and/orpolycyano acrylate can serve as both polymeric matrix and ligands. Manyof these ligands can further amplify the protecting effect of nickeland/or cobalt. Another additive, antioxidants, may also be optionallyadded into the composition. Nonlimiting examples of antioxidants caninclude hydrochinon, tannic acid, lignin and lignin fragments,polyunsaturated fatty acids and their esters, and/or pine oil. Alsotraditional corrosion prevention methods may be combined with thepresent method. For example, lead(II,II,IV)oxide may be a part of thecomposition. An iron plumbate layer may form on the surface of metalliciron. Iron plumbate can be hard, and further corrosion may be preventedor slowed down. The present composition can allow for a considerablereduction of lead content of the coating. The materials of thecomposition may be used wherever coatings will be used, including harshapplications such as marine coatings, coating of oil pipes, and/orchemical containers. In some applications, other kind of compounds suchas silica, alumina, titanium oxide, copper oxide, and/or tin oxide maybe added to increase hardness and/or biocidal capabilities. Thesecompounds may be microparticles about 0.1 μm to about 300 μm in size.These compounds may also be nanoparticles about 1 nm and about 2500 nmin size. Additionally, the composition described herein may furthercomprise sacrificial metal particles less noble than the metal substrateto which the composition contacts. The sacrificial metal particles lessnoble than the metal substrate to which the composition contacts mayinclude but is not limited to zinc, aluminum, and/or magnesium. Thesacrificial metal particles less noble than a metal substrate can alsobe microparticles, which may be about 0.1 μm to about 300 μm in size.The sacrificial metal particles less noble than a metal substrate canalso be nanoparticles about 1 nm and about 2500 nm in size. Wheremicroparticles or nanoparticles are used, the composition of thesacrificial metal particles less noble than a metal substrate may be0.00001% by weight. These sacrificial metal microparticles ornanoparticles less noble than a metal substrate may be easier to handlebecause they will not be so easily oxidized. Further, the sacrificialmetal particles less noble than a metal substrate may be regenerated.

Also described is the method of protecting a metal substrate using acomposition comprising sacrificial metal particles more noble than ametal substrate to which the composition contacts and carbonaceousmaterial that can form electrical contact between the sacrificial metalparticles. Within the method, the composition described herein can beapplied to a metal substrate in order to protect it from corrosion. Thecomposition may be a flowable material or a powder coating. The methodmay be used separately or in addition to other method(s) that may beused for corrosion protection. The method may also be repeated at leastonce. The method may also be used to prevent or reduce further corrosionthat may have already occurred on a metal substrate.

The embodiments have been described, hereinabove. It will be apparent tothose skilled in the art that the above composition and method mayincorporate changes and modifications without departing from the generalscope. It is intended to include all such modifications and alterationsin so far as they come within the scope of the appended claims or theequivalents thereof.

Having thus described the composition and method, it is now claimed:

1. A corrosion prevention composition comprising: sacrificial metalparticles, wherein the sacrificial metal particles comprise at least onemetal of nickel or cobalt; a polymeric matrix, wherein the polymericmatrix comprises at least one amino hardened epoxy; and carbonaceousmaterial that forms electrical contact between the sacrificial metalparticles, wherein the composition is adapted to form a layer on top ofa layer of iron (II) oxide on an associated metal substrate comprisingiron and is adapted to prevent oxidation of the layer of iron (II) onthe associated metal substrate from an iron (II) to an iron (III), andwherein the sacrificial metal particles have a higher reductionpotential than the associated metal substrate.
 2. The composition ofclaim 1, wherein the sacrificial metal particles are microparticles ornanoparticles, wherein the sacrificial metal particles comprise 0.00001%by weight to about 95% by weight of the composition.
 3. The compositionof claim 1, wherein the carbonaceous material comprises graphiticcarbon, wherein the graphitic carbon comprises at least one graphiticcarbon of microhorns, single-walled nanotubes, double-walled nanotubes,multi-walled nanotubes, graphite, and graphene.
 4. The composition ofclaim 1, wherein the carbonaceous material is functionalized, whereinthe carbonaceous material comprises about 0.1% by weight to about 20% byweight of the composition.
 5. The composition of claim 4, wherein thecarbonaceous material comprises about 0.1% by weight to about 4% byweight of the composition.
 6. The composition of claim 1, wherein thecomposition further comprises a flowable material, wherein the flowablematerial comprises at least one polymer of polyacrylate,polyacrylonitrile, polybitumeate, polyethylene, polypropylene,polybutadiene, polyurea, polyamide, polyimide, polyurethane,polyvinylchloride, aspartates, fluoropolymers, silicone, siloxanes,rubber, and epoxy.
 7. The composition of claim 1, wherein thecomposition further comprises cellulose, wherein the cellulose comprisesat least one cellulose of functionalized cellulose and amorphousfragmented cellulose.
 8. The composition of claim 1, wherein thecomposition further comprises an antioxidant, wherein the antioxidantcomprises at least one antioxidant of hydrochinon, tannic acid, lignin,lignin fragments, polyunsaturated fats, esters of polyunsaturated fats,and pine oil.
 9. The composition of claim 8, wherein the compositionfurther comprises aluminum i-propoxide.
 10. The composition of claim 1,wherein the composition further comprises trimethyl borate.
 11. Thecomposition of claim 1, wherein the composition further comprises leadoxide.
 12. The composition of claim 1, wherein the composition furthercomprises at least one compound of silica, alumina, titanium oxide,copper oxide, and tin oxide.
 13. The composition of claim 1, wherein thecomposition further comprises a second set of sacrificial metalparticles, wherein the second set of sacrificial metal particles have alower reduction potential than the associated metal substrate, whereinthe second set of sacrificial metal particles having a lower reductionpotential than the associated metal substrate are at least one of zinc,aluminum, and magnesium.
 14. A corrosion prevention compositioncomprising: sacrificial metal particles, the sacrificial metal particlescomprising at least one metal of nickel and cobalt; carbonaceousmaterial comprising multi-walled graphitic carbon that can formelectrical contact between the sacrificial metal particles; a flowablematerial comprising epoxy functionalities; and an antioxidant comprisingat least one antioxidant of hydrochinon, tannic acid, lignin, ligninfragments, polyunsaturated fats, esters of polyunsaturated fats, andpine oil, wherein the composition is adapted to form a layer on top of alayer of iron (II) oxide on an associated metal substrate comprisingiron and the composition is adapted to prevent oxidation of the layer ofiron (II) oxide on the associated metal substrate from an iron (II) toan iron (III).
 15. A corrosion prevention composition comprising:sacrificial metal particles, wherein the sacrificial metal particles aremolybdenum; carbonaceous material that forms electrical contact betweenthe sacrificial metal particles; a polymeric matrix, wherein thepolymeric matrix comprises at least one amino hardened epoxy; andwherein the composition is adapted to form a layer on top of a layer ofiron (II) oxide on an associated metal substrate comprising iron and thecomposition is adapted to prevent oxidation of the layer of iron (II)oxide on the associated metal substrate from an iron (II) to an iron(III), and wherein the sacrificial metal particles have a higherreduction potential than the associated metal substrate.
 16. Thecomposition of claim 15, wherein the sacrificial metal particlescomprise 0.00001% by weight to about 95% by weight of said composition.17. The composition of claim 15, wherein the carbonaceous materialcomprises graphitic carbon, wherein said graphitic carbon comprises atleast one graphitic carbon of microhorns, single-walled nanotubes,double-walled nanotubes, multi-walled nanotubes, graphite, and graphene.18. The composition of claim 15, wherein the polymeric matrix is aflowable material, wherein the flowable material comprises at least onepolymer of polyacrylate, polyacrylonitrile, polybitumeate, polyethylene,polypropylene, polybutadiene, polyurea, polyamide, polyimide,polyurethane, polyvinylchloride, aspartates, fluoropolymers, silicone,siloxanes, rubber, and epoxy.
 19. The composition of claim 15, whereinthe composition further comprises cellulose, wherein the cellulosecomprises at least one cellulose of functionalized cellulose andamorphous fragmented cellulose.
 20. The composition of claim 15, whereinthe composition further comprises an antioxidant, wherein theantioxidant comprises at least one antioxidant of hydrochinon, tannicacid, lignin, lignin fragments, polyunsaturated fats, esters ofpolyunsaturated fats, and pine oil.